/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: Lenovo
 * Date: 2025-05-24
 * Time: 14:53
 */
public class Test {
    public static void main(String[] args) {
        int sum=0;
        for (int i = 1; i <= 100; i++) {
            if(i%2==1)
                sum+=10*i+3;
            else
                sum-=10*i+3;
        }
        System.out.println(sum);
    }
}
